A CMOS-Compatible Composite MEMS Pirani Sensor With a Wide Detection Range and High Sensitivity

In this work, we report on a CMOS-compatible MEMS Pirani sensor that consists of a thermopile and a thermistor, which serves as the two sensing elements to achieve high sensitivity over a wide detection range. In the device, the thermistor, which is distributed at the hot ends of the thermopile, works not only as a highly sensitive Pirani sensor with a detection range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{-{1}}$ </tex-math></inline-formula>–<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\times 10^{{5}}$ </tex-math></inline-formula> Pa but also as a heater that provides Joule heat to the thermopile. Consequently, the thermopile functions as another sensitive Pirani sensor with a range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\times 10^{-{2}}$ </tex-math></inline-formula>–<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times 10^{{4}}$ </tex-math></inline-formula> Pa. With the combination of these two sensing elements, the device has an extended detection range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\times 10^{-{2}}$ </tex-math></inline-formula>–<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\times 10^{{5}}$ </tex-math></inline-formula> Pa, enabling various application scenarios, such as monitoring the vacuum conditions of semiconductor manufacturing equipment.